Amenorrhea is a condition in which a woman does not menstruate or experiences one or more missed menstrual periods. There are two types of amenorrhea: primary amenorrhea and secondary amenorrhea. Primary amenorrhea is when a girl does not get her period by age 15. Secondary amenorrhea is when a female has had a normal menstrual cycle, but stops getting them or has missed at least three consecutive menstrual periods. Less than one percent of girls in the United States have primary amenorrhea.

What causes amenorrhea? The most common cause of amenorrhea is pregnancy. Other things that may cause amenorrhea include problems with the reproductive organs or with the glands that help regulate hormone levels. The main sign of amenorrhea is not having a menstrual period. Other signs and symptoms that may occur vary depending on what is causing the condition. Other signs or symptoms that may appear with amenorrhea include hair loss, excess facial hair, pelvic pain, milky nipple discharge, headache, vision changes, or acne.

Causes of amenorrhea:

Being underweight: Having a very low body weight can cause amenorrhea. Being underweight can interfere with a woman’s hormones which can interfere with ovulation. This is why women who have eating disorders usually stop getting their period.

Uterine scarring: Asherman's syndrome can cause amenorrhea. This is when scar tissue builds up in the lining of the uterus which prevents the normal buildup and shedding of the uterine lining.

Natural causes: Amenorrhea may be caused by natural reasons such as pregnancy, breast-feeding, or menopause.

Polycystic ovary syndrome: Polycystic ovary syndrome causes an increase in hormones, which can cause amenorrhea. In a normal menstrual cycle, hormones are fluctuating.

Vaginal obstruction: If there is an obstruction or blockage in the vagina, it may cause amenorrhea.

Mental stress: Being mentally and emotionally stressed out can cause amenorrhea by interfering with your body’s hormones.

Excessive exercise: Participating in excessive physical exercise or activity can cause amenorrhea. This may be a result of losing too much weight, putting too much stress on your body, or engaging in activities that use up too much energy.

Contraceptives: Taking contraceptives, such as birth control pills, may cause amenorrhea. If a women decides to stop taking birth control, it could take a few months for her regular period to come back.

Thyroid problems: Having hyperthyroidism or hypothyroidism can cause amenorrhea.

Premature menopause: Women usually begin menopause around age 50. However, some women may experience menopause earlier, before age 40. This can lead to amenorrhea.

Being born without certain reproductive organs: Sometimes females may be born without a uterus, cervix or vagina, which can cause amenorrhea.